A Low Repetition Rate All-Active Monolithic Passively Mode-Locked Quantum-Dot Laser

Novel Light Source Integration Approaches for Silicon Photonics

“…The optical linewidth of the longitudinal modes is measured using a delayed self‐heterodyne method (see Figure b). A narrow optical linewidth below 250 kHz is achieved, which surpasses other works by at least one order of magnitude.…”

“…Monolithically integrated III‐V mode‐locked lasers (MLLs), acting as compact multi‐wavelength sources for telecom, covering a repetition rate of 10 GHz to 100 GHz have been heavily investigated over the past two decades . A few attempts of utilizing a long high‐quality cavity to improve mode‐locking performance have been made, although the improved performance is not satisfactory due to the high III‐V waveguide loss. One may bypass this obstacle by utilizing a hybrid integrated laser configuration that uses low‐loss silicon waveguides as an external cavity and high performance III‐V heterostructure for making semiconductor optical amplifiers (SOAs) and saturable absorbers (SAs) …”

Investigation of monolithic passively mode-locked quantum dot lasers with extremely low repetition frequency

“…Unless otherwise specified, in this paper, we considered a monolithic two-section QD ML laser (as shown in Figure 1a) with active region consisting of fivefold stack of selfassembled InAs QD layers and with a saturable absorber (SA) length L SA of 2 mm, gain section length L g of 18 mm (the corresponding fundamental repetition frequency is 2.4 GHz), ridge width W of 6 μm, high-reflection coating at the SA side facet with reflectivity R 0 = 95%, and the cleaved output facet with reflectivity R L = 33%. Indeed, this monolithic laser, used in our numerical simulation, has the same waveguide structure parameters to those used in the experimental studies in [3].…”

“…Generally, high repetition frequency QD ML lasers (from tens of GHz to hundreds of GHz) and their performance improvement are the focus of many papers (see review paper [1] and references there). However, only few papers study the monolithic QD ML lasers with relatively low repetition frequency and, especially, their dynamical regimes [3,4]. Indeed, in some applications, such as micromachining and two-photon microscopy, periodic highpower pulse sequences with much lower repetition rate are more desirable.…”

Monolithically integrated selectable repetition-rate laser diode source of picosecond optical pulses

“…The repetition rate issue has been addressed monolithically, for example by Cheung et al [6] who have demonstrated the emission of 36 ps pulses at 1 GHz from a 41 mm long device, and Li et al [7] who have demonstrated passive modelocking at a fundamental repetition rate of 2.1 GHz in a 20 mm long monolithic two-section quantum dot laser. The peak powers and repetition rates of these low repetition rate lasers are ultimately limited by the effects of large material losses, nanosecond gain recovery times, and high dispersion, all of which become more problematic as cavity lengths increase.…”